In this article, I talk about fear and aggression pheromones. Often a tense situation can arise when two animals of the same species that are strangers to each other come together. Their encounter may lead to aggressive behavior that involves signaling and creating with odors.

Animals Use Pheromones To Mark Territory

Such encounters often take place among lemurs, agile animals related to monkeys. Lemurs live only on the island of Madagascar, off the southeastern coast of Africa. When two male lemurs that are strangers cross paths, they sometimes engage in a rather bizarre activity called a “stink fight.”

To prepare for a stink ﬁght, lemurs spread pheromone secretions over themselves and their immediate surroundings. They coat their hands, feet, and even their tails with pheromone secretions produced by special glands on their chests and wrists. Now armed with odors, the two animals approach each other, waving their freshly scented tails in the air and making scent marks on the surrounding vegetation with their pheromone-covered hands and feet. ​One animal may advance a little and then retreat as the other comes toward him. Each time a lemur advances, he takes care to place his own pheromone marks directly over those of the other lemur, thus destroying the scent of his opponent in that spot. The ﬁght may go back and forth like this for more than an hour before one animal eventually gives up and retreats for good.

Trail Pheromones

Pheromones can be released into the air or deposited on a surface to form a trail that other animals can follow. A wide variety of animals, including ants, snails, and snakes, lay pheromone trails. Trail pheromones in ants have been studied extensively. As an ant scurries along, it can deposit pheromone secretions from a variety of glands on its legs and abdomen.

​These trails are used to show the way to food sources, to direct other ants to a new location for a nest, or to help the trail-laying individual find its way back home. Unlike alarm pheromones, which tend to disperse rapidly, trail pheromones are much more persistent and the chemical messages they convey last much longer. Learn how they affect humans at http://chrshrt112.typepad.com

Information Pheromones

Being able to recognize one’s home, parents, or members of one’s group is necessary for the survival of many animals, and pheromones play an important role in this recognition. For instance, bees appear to recognize their own nest by its characteristic smell. Many substances probably contribute to this “colony odor,” but the types and amounts of pheromones present certainly are important components.